Novel thiophene derivatives
Thiophene derivatives having utility as blood lipid lowering agents and as antiobesity agents are disclosed.
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A solution of 116.55 g (0.971 mole) of methyl-3-mercaptopropionate in 220 ml of dry methanol at -20.degree. was treated with 52.46 g (0.971 mole) of sodium methoxide. After 20 minutes, a solution of 203.0 g (0.971 mole) of ethyl-2-bromovalerate in 150 g of dry methanol was added dropwise. The reaction was allowed to warm to room temperature and stirred overnight. The methanol was evaporated and the residue was partitioned between ether/water. The organic phase was washed with 10% bicarbonate solution and water. After drying over magnesium sulfate, the ether was evaporated to yield 130 g (0.524 mole, 54%) of methyl-4-thia-5-carbomethoxyoctanoate as a colorless oil.
EXAMPLE 2To a suspension of 54.0 g (1.0 mole) of sodium methoxide in 500 ml of anhydrous benzene was added dropwise at 25.degree., 130 g (0.524 mole) of methyl-4-thia-5-carbomethoxyoctanoate. The mixture was stirred overnight and poured into ice-water. The aqueous phase was extracted with benzene/ether, 1:1, and then acidified to pH 1 with 6 N HCl. The product, which partially separates from the water at this point, is taken up in methylene chloride. The aqueous layer is further extracted with methylene chloride. The combined organic phases are dried and evaporated to yield 94.0 g. (0.466 mole, 89%) of pure 4-carbomethoxy-3-keto-2-propyl-tetrahydrothiophene as a colorless oil.
EXAMPLE 3A solution of 94.0 g (0.465 mole) of 4-carbomethoxy-3-keto-2-propyl-tetrahydrothiophene in 250 ml of dry pyridine was treated with 40.0 (0.576 mole) of hydroxylamine hydrochloride at 25.degree.. The reaction was stirred overnight at room temperature. The solvent was evaporated and the residue was partitioned between 1 N HCl and methylene chloride. The organic phase was dried over sodium sulfate and evaporated to afford 100 g. (0.461 mole, 99%) of pure 4-carbomethoxy-3-keto-2-propyl-tetrahydrothiophene oxime as a colorless oil.
EXAMPLE 4Gaseous hydrogen chloride was bubbled into one liter of anhydrous ether in which 100.0 g (0.461 mole) of 4-carbomethoxy-3-keto-2-propyl-tetrahydrothiophene oxime had been dissolved. This process was carried out at 0.degree. for one hour. The reaction flask was stoppered with a drying tube and allowed to stir at room temperature overnight. The solvent was evaporated until the product crystallized. The white solid was collected by filtration and washed well with ether to afford 60.0 g (0.255 mole, 55%) of 3-amino-4-carbomethoxy-2-N-propylthiophene hydrochloride, m.p. 178.degree.-180.degree.. The product was recrystallized from methanol/ether to yield 50.0 g (0.212 mole, 46%) of pure 3-amino-4-carbomethoxy-2-n-propylthiophene hydrochloride, m.p. 180.degree.-181.degree..
EXAMPLE 5 Fatty Acid and Cholesterol Synthesis in Isolated HepatocytesFemale Charles River rats are fasted 48 hours, then meal fed a 1% corn oil, 70% glucose diet for 7 to 14 days from 8-11 a.m. The isolated rat hepatocytes are prepared by perfusing the liver in situ. The hepatocytes are incubated in an oscillating water bath at 37.degree. C. for 60 minutes. Each flask contains a total of 2.1 ml volume, consisting of 1 ml isolated rat hepatocytes (10-20 mg dry weight cells), 1 ml Krebs-Henseleit bicarbonate buffer pH 7.4, 16.5 mM glucose, 1 .mu.mole L-alanine, 1 .mu.Ci [U-.sup.14 C]alanine, 1 mCi .sup.3 H.sub.2 O, and 2 mM inhibitor in H.sub.2 O or DMSO at p.sup.H 7.4 (unless otherwise specified). All incubations are done in triplicate and all experiments are repeated at least twice. CO.sub.2 is collected in each flask following the 60 minutes incubation by adding 0.3 ml ethanolamine:2-methoxy-ethanol (1:2 ) to the center well, 0.4 ml of 62.5% citric acid to the cell media, and incubating for 45 minutes. The contents of the center well are transferred to scintillation counting fluid and .sup.14 CO.sub.2 content is determined. The media is saponified, acidified (only for determining the rate of lipogenesis) and extracted with hexane. At this stage the lipids are either counted (to determine the rate of lipogenesis) or precipitated with digitonin, washed, and counted (to determine the rate of cholesterogenesis). The conversion of .sup.3 H.sub.2 O and [.sup.14 C]alanine into fatty acids or sterols is determined in a PDS/3, Mark II liquid scintillation counting system. Data are expressed as nmoles .sup.3 H.sub.2 O and [.sup.14 C]alanine converted into fatty acids or cholesterol, and nmoles [.sup.14 C]alanine oxidized to .sup.14 CO.sub.2 per mg dry weight cells per 60 minutes. The results are set forth in Table I.
TABLE I
__________________________________________________________________________
EFFECT OF 3-AMINO-4-CARBOMETHOXY-2- N--PROPYLTHIOPHENE
HYDROCHLORIDE ON LIPID SYNTHESIS AND CO.sub.2 PRODUCTION IN ISOLATED
RAT HEPTOCYTES.sup.a
CO.sub.2
Fatty Acid Synthesis
Cholesterol Synthesis
Production
Dose [.sup.14 C]alanine
.sup.3 H.sub.2 O
[.sup.14 C]alanine
Treatment nM .sup.3 H.sub.2 O
converted
converted
[.sup.14 C]alanine
converted
__________________________________________________________________________
AS % OF CONTROL
Control (DMSO)
-- 100 100 100 100 100
3-Amino-4-carbo-
0.50
17* 9* 28* 19* 49*
methoxy-2-n-propyl-
0.25
21* 10* 29* 21* 50*
thiophene hydro-
0.10
18* 10* 35* 23* 53*
chloride 0.05
18* 11* 33* 26* 54*
0.01
30* 19* 49* 31* 73*
__________________________________________________________________________
.sup.a Each flask contained 13.7 mg cells dry weight and 25 .mu.l DMSO.
Each value is the mean of 2 to 14 determinations.
*Statistically different from control value.
EXAMPLE 6
Fatty Acid and Cholesterol Synthesis In Vivo
Rats are prepared by fasting 48 hours and refeeding a 1% corn oil 70% glucose diet for several days (5-15). On the experimental day, rats are dosed 30 or 60 minutes before the 3 hour meal by oral intubation, or 60 minutes after the end of the 3 hour meal by intraperitoneal injection. (The dose concentrated is a mmoles/kg/5-10 ml H.sub.2 O or 1% gum arabic depending on the solubility of the compound.) Rats are sacrificed by decapitation after a 30 minute pulse consisting of: 1mCi.sup.3 H.sub.2 O,5 .mu.Ci[U-.sup.14 C]alanine, 12.3 mg. alanine, and 30.6 mg .alpha.-ketoglutaric acid in 0.25 mg saline, given at the end of the 3 hour meal by i.v. injection into the tail vein. Blood was collected, allowed to clot and the serum analyzed for triglyceride and cholesterol levels. The livers are quickly excised, saponified, and acidified (only for determining the rate of lipogenesis) and extracted with hexane. At this stage the lipids are either counted (to determine the rate of lipogenesis) or precipitated with digitonin, washed, and counted (to determine the rate of cholesterogenesis). The conversion of .sup.3 H.sub.2 O and [.sup.14 C]alanine into fatty acids or sterols is determined in a PDS/3, Mark II liquid scintillation counting system. Data are expressed as moles .sup.3 H.sub.2 O nmoles converted into fatty acids and cholesterol per g liver per 30 minutes. The results are set forth in Tables II-VII.
TABLE II
__________________________________________________________________________
EFFECT OF INTRAPERITONEAL ADMINISTRATION OF 3-AMINO-4-CARBOMETHOXY-
2-N--PROPYLTHIOPHENE HYDROCHLORIDE ON IN VIVO LIPOGENESIS
AND CHOLESTEROGENESIS
Fatty Acid Synthesis.sup.b
Cholesterol Synthesis.sup.b
Dose nmoles[.sup.14 C]alanine
.mu.moles .sup.3 H.sub.2 O
nmoles[.sup.14 C]alanine
Treatment.sup.a
mmoles/kg
converted/g/30 min.
converted/g/30 min.
converted/g/30 min
__________________________________________________________________________
Control (1% gum arabic)
-- 614 .+-. 66
1.36 .+-. 0.07
35.7 .+-. 3.2
3-Amino-4-carbomethoxy-
0.1 251 .+-. 36**
0.85 .+-. 0.06***
17.6 .+-. 1.9*
2-n-propylthiophene
hydrochloride
__________________________________________________________________________
.sup.a Charles River CD rats (5-6 rats per group at 150-170 g) were faste
48 hours, then mealfed a high carbohydrate diet for 14 days. On the
experimental day, the rats were given an i.p. dose of
3amino-4-carbomethoxy-2-n-propylthiophene hydrochloride (0.1 mmoles/kg/10
ml 1% gum arabic) immediately after the 3 hour meal, followed, 30 minutes
later, by an i.v. pulse. One hour after the i.p. injection the rats were
sacrificed and rates of synthesis determined.
.sup.b Data are expressed as .mu.moles .sup.3 H.sub.2 O and moles[ .sup.1
C]alanine converted into fatty acids or cholesterol per g liver per 30
minutes.
*p > 0.05
**p > 0.01
***p > 0.001.
TABLE III
__________________________________________________________________________
EFFECT OF 3-AMINO-4-CARBOMETHOXY-2- N--PROPYLTHIOPHENE
HYDROCHLORIDE ON SERUM LIPIDS.sup.a
Administration
Dose Triglycerides
Cholesterol
Treatment Route mmoles/kg
mg % mg %
__________________________________________________________________________
Control (%) gum arabic
i.p. -- 67 .+-. 4
116 .+-. 7
3-Amino-4-carbomethoxy-2-
i.p. 0.1 51 .+-. 3**
105 .+-. 11
n-propylthiophene hydro-
chloride
__________________________________________________________________________
.sup.a Charles River CD rats (5-6 rats per group at 150-170 g) were faste
48 hours, then mealfed a high carbohydrate diet for 14 days. On the
experimental day, the rats were given an i.p. dose of
3amino-4-carbomethoxy-2-n-propylthiophene hydrochloride (0.1 mmoles/kg/10
ml % gum arabic) immediately after the 3 hour meal, followed, 30 minutes
later, by an i.v. pulse. One hour after the i.p. injection the rats were
sacrificed and rates of synthesis determined.
**p > 0.01.
TABLE IV
__________________________________________________________________________
EFFECT OF ORAL ADMINISTRATION OF 3-AMINO-4-CARBOMETHOXY-2- N--PROPYL-
THIOPHENE HYDROCHLORIDE ON IN VIVO FATTY ACID SYNTHESIS
Fatty Acid Synthesis.sup.b
Dose .mu.moles .sup.3 H.sub.2 O
% of nmoles[.sup.14 C]alanine
% of
Treatment.sup.a
mmoles/kg
converted/g/30 min.
Control
converted/g/30 min.
Control
__________________________________________________________________________
Control (1% gum arabic)
-- 19.6 .+-. 2.4
100 473 .+-. 76
100
3-Amino-4-carbomethoxy-
1.2 7.1 .+-. 1.7**
36 162 .+-. 60**
34
2-n-propylthiophene
hydrochloride
__________________________________________________________________________
.sup.a Charles River CD rats (6 rats per group at 160-180 g) were fasted
48 hours, then mealfed a high carbohydrate diet for 18 days. On the
experimental day, rats were given an oral dose (1% gum arabic or
3amino-4-carbomethoxy-2-n-propylthiophene hydrochloride in 1% gum arabic
at the above concentrations) 30 minutes before the beginning of the meal.
At the end of the 3 hour meal, the rats were given an i.v. pulse,
sacrificed 30 minutes later and rates of synthesis were determined.
.sup.b Data are expressed as .mu.moles .sup.3 H.sub.2 O and nmoles
[.sup.14 C]alanine converted into fatty acids per g liver per 30 minutes.
*p > 0.05
**p > 0.01.
TABLE V
__________________________________________________________________________
EFFECT OF ORAL ADMINISTRATION OF 3-AMINO-4-CARBOMETHOXY-2- N--PROPYL-
THIOPHENE HYDROCHLORIDE ON IN VIVO CHOLESTEROL SYNTHESIS
Dose .mu.moles .sup.3 H.sub.2 O
% of nmoles[.sup.14 C]alanine
% of
Treatment.sup.a
nmoles/kg
converted/g/30 min.
Control
converted/g/30 min.
Control
__________________________________________________________________________
Control (1% gum arabic)
-- 1.35 .+-. 0.04
100 33.0 .+-. 3.1
100
3-Amino-4-carbomethoxy-
1.2 0.88 .+-. 0.16*
65 15.2 .+-. 3.2**
46
2-n-propylthiophene
hydrochloride
3-Amino-4-carbomethoxy-
0.4 0.96 .+-. 0.05***
71 17.4 .+-. 0.9***
53
2-n-propylthiophene
hydrochloride
__________________________________________________________________________
.sup.a Charles River CD rats (6 rats per group at 160-180 g) were fasted
48 hours, then mealfed a high carbohydrate diet for 18 days. On the
experimental day, rats were given an oral dose (1% gum arabic or
3amino-4-carbomethoxy-2-n-propylthiophene hydrochloride in 1% gum arabic
at the above concentrations) 30 minutes before the beginning of the meal.
At the end of the 3 hour meal, the rats were given an i.v. pulse,
sacrificed 30 minutes later, and rates of synthesis were determined.
.sup.b Data are expressed as .mu.moles .sup.3 H.sub.2 O and nmoles
[.sup.14 C]alanine converted into cholesterol per g liver per 30 minutes.
*p > 0.05
**p > 0.01
***p > 0.001.
EXAMPLE 7
A solution of 66.29 g. (0.552 mole) methyl-3-mercaptopropionate in 50 ml. anhydrous methanol was cooled to 0.degree. and treated with 120 ml. of a 25% solution of sodium methoxide in methanol. To this solution was added dropwise 100 g. (0.552 mole) of ethyl-2-bromopropionate in 100 ml. anhydrous methanol. The reaction was allowed to proceed at 25.degree. overnight. The solvent was evaporated, and the residue was partitioned between ether and 10% sodium bicarbonate. The aqueous phase was further extracted with ether. The combined organic extracts were dried over magnesium sulfate and evaporated to yield 121.40 g. (100%) of 2-methyl-3-thia-1,6-hexanedionic acid-1-ethyl-6-methyl ester as a pale yellow oil.
Similarly, 61.4 g. (0.51 mole) of methyl-3-mercaptopropionate was combined with 106.8 g. (0.51 mole) of ethyl-2-bromovalerate to yield 120.91 g. (96%) of 2-isopropyl-3-thia-1,6-hexanedionic acid-1-ethyl-6-methyl ester as a colorless oil.
EXAMPLE 8A solution of 121.4 g. (0.552 mole) of 2-methyl-3-thia-1,6-hexanedioic acid-1-ethyl-6-methyl ester in 90 ml. dry benzene was added dropwise to a suspension of 30 g. anhydrous sodium methoxide in 200 ml. dry benzene. The reaction was allowed to proceed overnight. The mixture was partitioned between water/ether. The aqueous phase was further extracted with benzene. The aqueous phase was then acidified to pH 1 with 6 N HCl and extracted three times with methylene chloride. The methylene chloride extracts were combined, dried over sodium sulfate, and evaporated to afford 79.17 g. (82%) of pure 4-carbomethoxy-3-keto-2-methyltetrahydrothiophene as a colorless oil.
Similarly, 120.91 g. of 2-isopropyl-3-thia-1,6-hexanedionic acid-1-ethyl-6-methyl ester was converted to 91.0 g. (93%) of 4-carbomethoxy-2-isopropyl-3-keto-tetrahydrothiophene as a colorless oil.
EXAMPLE 9A solution of 37.26 g. (0.214 mole) of 4-carbomethoxy-3-keto-2-methyltetrahydrothiophene in 100 ml. anhydrous pyridine was treated with 18.0 g. (0.261 mole) hydroxylamine hydrochloride. The mixture was stirred 24 hours at 25.degree.. The reaction was concentrated and partitioned between 1 N hydrochloric acid/methylene chloride. The aqueous phase was extracted two times with methylene chloride. The combined organic extracts were dried and evaporated to yield 40.1 g (99%) of pure 4-carbomethoxy-3-keto-2-methyltetrahydrothiophene oxime as a colorless oil.
Similarly, 52.8 g. (0.26 mole) of 4-carbomethoxy-2-isopropyl-3-keto-tetrahydrothiophene was converted to 49.0 g. (0.226 mole), 87%) of 4-carbomethoxy-2-isopropyl-3-keto-tetrahydrothiophene oxime as a colorless oil.
EXAMPLE 10A solution of 41.1 g. (0.217 mole) of 4-carbomethoxy-3-keto-2-methyltetrahydrothiophene oxime in 600 ml. anhydrous ether, previously saturated with gaseous hydrogen chloride at 0.degree., was allowed to stir at 25.degree. overnight. The separated solid was collected, washed well with ether, and dried to afford 33.2 g. Evaporation of the filtrate yielded after recrystallization of the residue an additional 4.2 g. to afford a total yield of pure 3-amino-4-carbomethoxy-2-methylthiophene hydrochloride of 37.4 g. (84%). The compound melts 191.degree.-192.degree..
Similarly, 49.12 g. (0.226 mole) of 4-carbomethoxy-2-isopropyl-3-keto-tetrahydrothiophene was converted to 18.49 g. (35%) of 3-amino-4-carbomethoxy-2-isopropylthiophene hydrochloride, m.p. 185 (dec.).
EXAMPLE 11A solution of 2.07 g (0.010 mole) of 3-amino-4-carbomethoxy-2-methylthiophene hydrochloride in 35 ml. methanol was treated with 23 ml. 1 N sodium hydroxide. The mixture was heated under reflux 0.5 hour, cooled, and poured into brine. The pH was adjusted to 5 and extracted seven times with methylene chloride/methanol, 4:1. The organic extracts were combined, dried, and evaporated to yield 1.23 g. (78%) of pure 3-amino-4-carboxy-2-methylthiophene, m.p. 162.degree.-164.degree.. The compound was recrystallized from ethyl acetate/pentane to afford an analytical sample, m.p. 163.degree.-164.degree..
Similarly, 5.0 g. (0.021 mole) of 3-amino-4-carbomethoxy-2-isopropylthiophene hydrochloride was converted into 3.3 g. (84%) of 3-amino-4-carboxy-2-isopropylthiophene, m.p. 117.degree.-118.degree..
Similarly, 1.41 g. (0.00708 mole) 3-amino-4-carbomethoxy-2-propylthiophene hydrochloride was converted into 0.625 g. (48%) of 3-amino-4-carboxy-2-propylthiophene, m.p. 144.degree.-145.degree..
EXAMPLE 12A solution of 1.03 g. (0.005 mole) of 3-amino-4-carbomethoxy-2-methylthiophene hydrochloride in 30 ml. water was treated with a solution of 0.45 g. potassium cyanate in 10 ml. water. A white solid separated. The mixture was extracted three times with methylene chloride. The organic extracts were combined dried, and evaporated to yield 0.82 g. (77%) of pure 4-[(aminocarbonyl)amino]-5-methyl-3-thiophenecarboxylic acid methyl ester. The compound could be recrystallized from ethyl acetate to give a white solid, m.p. 194.degree.-195.degree..
The following examples 13-16 illustrate pharmaceutical compositions containing 3-amino-4-carbomethoxy-2-n-propylthiophene hydrochloride (active compound).
EXAMPLE 13 ______________________________________
Capsule Formulation
Per Capsule
______________________________________
Active compound 10 mg
Lactose, U.S.P. 165 mg
Corn Starch, U.S.P.
30 mg
Talc, U.S.P. 5 mg
Total Weight 210
mg
______________________________________
Procedure
1. Active compound, lactose and corn starch were mixed in a suitable mixer.
2. The mixture was further blended by passing through a Fitzpatrick Comminuting Machine with a 1A screen with knives forward.
3. The blended powder was returned to the mixer, the talc added and blended thoroughly.
4. The mixture was filled into 4 hard shell gelatin capsules on a Parke Davis capsulating machine. (Any similar type capsulating machine may be used).
EXAMPLE 14 ______________________________________
Capsule Formulation
Per Capsule
______________________________________
Active compound 50 mg
Lactose, U.S.P. 125 mg
Corn Starch, U.S.P.
30 mg
Talc, U.S.P. 5 mg
Total Weight 210
mg
______________________________________
Procedure
1. Active compound was mixed with lactose and corn starch in a suitable mixer.
2. The mixture was further blended by passing through a Fitzpatrick Comminuting Machine with a 1A screen with knives forward.
3. The blended powder was returned to the mixer, the talc added and blended thoroughly.
4. The mixture was filled into 4 hard shell gelatin capsules on a Parke Davis capsulating machine.
EXAMPLE 15 ______________________________________
Tablet Formulation
Per Tablet
______________________________________
Active compound 25.00 mg
Dicalcium Phosphate Dihydrate,
175.00 mg
Unmilled
Corn Starch 24.00 mg
Magnesium Stearate 1.00 mg
Total Weight 225.00
mg
______________________________________
Procedure
1. Active compound and corn starch were mixed together and passed through an 00 screen in Model "J" Fitzmill with hammers forward.
2. This premix was then mixed with dicalcium phosphate and one-half of the magnesium stearate, passed through a 1A screen in Model "J" Fitzmill with knives forward, and slugged.
3. The slugs were passed through a 2A plate in a Model "D" Fitzmill at slow speed with knives forward, and the remaining magnesium stearate was added.
4. The mixture was mixed and compressed.
EXAMPLE 16 ______________________________________
Tablet Formulation
Per Tablet
______________________________________
Active compound 100 mg
Lactose, U.S.P. 202 mg
Corn Starch, U.S.P.
80 mg
Amijel Bo11* 20 mg
Calcium Stearate 8 mg
Total Weight 410
mg
______________________________________
A prehydrolyzed food grade corn starch. Any similar prehydrolyzed corn starch may be used.
Procedure1. Active compound, lactose, corn starch, and Amijel B011 were blended in a suitable mixer.
2. The mixture was granulated to a heavy paste with water and the moist mass was passed through a 12 screen. It was then dried overnight at 110.degree. F.
3. The dried granules were passed through a 16 screen and transferred to a suitable mixer. The calcium stearate was added and mixed until uniform.
4. The mixture was compressed at a tablet weight of 410 mg, using tablet punches having a diameter of approximately three-eight inch. (Tablets may be either flat or biconvex and may be scored if desired).
EXAMPLE 17 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochlorideTo a solution of 125 g. (1.02 mols) of methyl-3-mercaptopropionate in 75 ml. of dry methanol was added dropwise at 0.degree. 249 ml. (1.122 mols) of 25% sodium methoxide/methanol (Aldrich). The resulting mixture was treated dropwise at 0.degree. with 200 g. (1.02 mols) of ethyl-2-bromobutyrate in 75 ml. of dry methanol. The cooling bath was removed and the reaction stirred overnight at 25.degree.. The mixture was concentrated and partitioned between water and methylene chloride. The organic extracts were dried and evaporated to yield 229 g. (96%) of 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochloride as a colorless oil.
EXAMPLE 18 4-carbomethoxy-3-keto-2-ethyltetrahydrothiopheneTo a suspension of 63.5 g. (1.176 mols) of sodium methoxide in 300 ml. of dry benzene was added dropwise at 25.degree. 229 g. (0.98 mol) of 2-ethyl-3-thia-1,6-hexanedioic-1-ethyl-6-methyl ester in 200 ml. of dry benzene. The reaction mixture warms up during the addition. After stirring overnight at room temperature, the reaction was poured into 800 ml. of water, and the benzene layer was further extracted with 200 ml. of water. The aqueous phases were combined, carefully acidified with 6 N HCl, and extracted three times with methylene chloride/methanol, 5:1. The organic extracts were dried and evaporated to afford 149.7 g. (82%) of pure 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene as a colorless oil.
EXAMPLE 19 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene oximeTo a solution of 276.1 g. (1.47 mols) of 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene in 500 ml. of anhydrous pyridine was added in several portions 121.6 g. (1.176 mols) of hydroxylamine hydrochloride. The reaction was allowed to proceed for 20 hours at 25.degree., concentrated, and partitioned between methylene chloride/3 N HCl. The aqueous phase was backwashed two times with methylene chloride/methanol 5:1. The organic phases were dried and evaporated to afford 253 g. (82%) of pure 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene oxime as a pale yellow oil.
EXAMPLE 20 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochlorideA solution of 253 g. (1.25 mols) of 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene oxime in 2 l. of anhydrous ether was treated at 25.degree. with a stream of gaseous hydrogen chloride for one hour. The reaction was seeded with 0.5 g. of authentic product and stirred overnight at 25.degree.. The crude product was filtered, washed with anhydrous ether, and recrystallized from methanol/ether to afford 173 g. (62%) of 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochloride, m.p. 164.degree..
In subsequent experiments, the ester hydrochloride was recrystallized from methanol/acetonitrile to afford pure 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochloride, m.p. 174.degree.-175.degree..
EXAMPLE 21 4-amino-5-ethyl-3-thiophenecarboxylic acidA sample of 10.0 g. (0.0452 mole) of 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochloride in 100 ml. methanol was treated with 105 ml. 1 N sodium hydroxide and heated under reflux for one hour. The resulting mixture was cooled and partitioned between water (pH 4.5) and methylene chloride/methanol (4:1). The aqueous phase was further extracted with methylene chloride/methanol (4:1) five additional times. The organic extracts were combined, dried over sodium sulfate and evaporated to yield 6.4 g. (81%) of 4-amino-5-ethyl-3-thiophenecarboxylic acid. The product was recrystallized from ethyl acetate/pentane to yield a pure sample, m.p. 132.degree.-133.degree. C.
EXAMPLE 22 4-amino-5-ethyl-3-thiophenecarboxylic acid ethyl ester hydrochlorideA sample of 1.10 g. (64.2 mmols) of 4-amino-5-ethyl-3-thiophenecarboxylic acid was dissolved in 20 ml. absolute ethanol which had been previously saturated with gaseous hydrogen chloride. The resulting reaction was heated under reflux for 22 hours, cooled and evaporated to afford 1.081 g. (71%) of pure 4-amino-5-ethyl-3-thiophenecarboxylic acid ethyl ester hydrochloride, m.p. 142.degree.-143.degree. C. (absolute ethanol).
EXAMPLE 23 4-amino-5-propyl-3-thiophenecarboxylic acid ethyl ester hydrochlorideA sample of 1.50 g. (8.097 mmols) of 4-amino-5-propyl-3-thiophenecarboxylic acid was dissolved in 75 ml. absolute ethanol which had been previously saturated with gaseous hydrogen chloride. The resulting reaction was heated under reflux for 24 hours, cooled and evaporated to afford 1.43 g. (71%) of pure 4-amino-5-propyl-3-thiophenecarboxylic acid ethyl ester hydrochloride, m.p. 144.degree. C. (dec.) after recrystallization from ethyl acetate.
EXAMPLE 24 4-amino-5-ethyl-3-thiophenecarboxylic acid isopropyl ester hydrochlorideA sample of 1.02 g. (4.610 mmols) of 4-amino-5-ethyl-3-thiophenecarboxylic acid was dissolved in 50 ml. of isopropanol which had been previously saturated with gaseous hydrogen chloride. The resulting reaction was heated under reflux for 48 hours, cooled and evaporated to afford 0.927 g. (81%) of pure 4-amino-5-ethyl-3-thiophenecarboxylic acid isopropyl ester hydrochloride, m.p. 159.degree. C. (dec.) after recrystallization from isopropanol/ether.
EXAMPLE 25 2-butyl-3-thia-1,6-hexanedioic-1-ethyl-6-methyl esterTo a solution of 106.8 g. (0.89 mol) of methyl-3-mercaptopropionate in 100 ml. dry methanol at 0.degree. C. was added dropwise 193 ml. (0.98 mol) of a 25% solution of sodium methoxide in methanol. To the resulting mixture 200 g. (0.89 mol) of ethyl-2-bromovalerate in 100 ml. dry methanol was added dropwise at 0.degree. C. The reaction was allowed to proceed at 25.degree. C., overnight. After evaporation of the solvent, the residue was partitioned between water/methylene chloride, and the aqueous phase was further extracted (2x) with methylene chloride/methanol (4:1). The organic extracts were dried over sodium sulfate and evaporated to yield 213.25 g. (92%) of pure 2-butyl-3-thia-1,6-hexanedioic-1-ethyl-6-methyl ester as a colorless oil.
EXAMPLE 26 4-carbomethoxy-3-keto-2-butyltetrahydrothiopheneA solution of 213.25 g. (0.81 mol) of 2-butyl-3-thia-1,6-hexanedioic-1-ethyl-6-methyl ester in 400 ml. dry benzene was added dropwise to a suspension of 48.0 g. (0.89 mol) of anhydride sodium methoxide in 200 ml. dry benzene. The resulting mixture was stirred overnight at room temperature. The reaction was partitioned between water/ether, and the aqueous phase was further extracted with benzene (1x). After acidification to pH 1 with concentrated hydrochloric acid, the aqueous phase was extracted (3x) with methylene chloride. The organic extracts were combined, dried over sodium sulfate and evaporated to yield 96.5 g. (55%) of pure 4-carbomethoxy-3-keto-2-butyltetrahydrothiophene as a colorless oil.
EXAMPLE 27 4-carbomethoxy-3-keto-2-butyltetrahydrothiophene oximeA sample of 96.5 g. (0.45 mol) of 4-carbomethoxy-3-keto-2-butyltetrahydrothiophene in 170 ml. pyridine was treated with 37.3 g. (0.54 mol) hydroxylamine hydrochloride and stirred overnight at 25.degree. C. The resulting reaction was concentrated in vacuo and partitioned between 3 N hydrochloride acid/methylene chloride. The aqueous phase was further extracted (2x) with methylene chloride/methanol (4:1). The organic extracts were combined, dried over sodium sulfate and evaporated to afford 101 g. (97%) of pure 4-carbomethoxy-3-keto-2-butyltetrahydrothiophene oxime as a colorless oil.
EXAMPLE 28 4-amino-5-butyl-3-thiophenecarboxylic acid methyl ester hydrochlorideA sample of 101 g. (0.437 mol) of pure 4-carbomethoxy-3-keto-2-butyltetrahydrothiophene oxime was dissolved in 600 ml. absolute ether. Gaseous hydrogen chloride was introduced at 0.degree. C. over the course of one hour. The resulting reaction was stirred overnight at 25.degree. C. and evaporated to afford 109 g. (100%) of crude 4-amino-5-butyl-3-thiophenecarboxylic acid methyl ester hydrochloride. The product was purified by recrystallization from ethyl acetate/pentane to afford a white solid, m.p. 120.degree. C. (dec.).
EXAMPLE 29 4-acetamido-5-ethyl-3-thiophenecarboxylic acid methyl esterA solution of 11.085 g. (0.05 mol) of 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochloride in 50 ml. anhydride pyridine was treated with 6.0 ml. acetic anhydride in one portion at 25.degree. C. The resulting reaction was stirred at room temperature for 3.0 hours, concentrated, and partitioned between 1 N hydrochloric acid methylene chloride. The aqueous phase was further extracted (2x) with methylene chloride. The organic extracts were combined, dried over sodium sulfate and evaporated to yield 11.17 g. (98%) of pure 4-acetamido-5-ethyl-3-thiophenecarboxylic acid methyl ester, m.p. 85.degree.-86.degree. C. (benzene/hexane).
EXAMPLE 30 5-ethyl-4-ethylaminothiophene-3-carboxylic acid methyl ester hydrochlorideA solution of 7.4 g. (0.0326 mol) of 4-acetamido-5-ethyl-3-thiophenecarboxylic acid methyl ester in 70 ml. absolute tetrahydrofuran was treated dropwise with 52 ml. of a 1 N diborane/tetrahydrofuran solution at 25.degree. C. The reaction was stirred overnight at room temperature, quenched with water (dropwise) and partitioned between concentrated ammonium hydroxide/methylene chloride. The aqueous phase was further extracted (2x) with methylene chloride/methanol (4:1). The organic extracts were combined, dried over sodium sulfate and evaporated to yield 7.3 g. of residue. The residue was chromatographed over a one kilogram silica gel column eluting with chloroform/methanol (9:1). 5-ethyl-4-ethylaminothiophene-3-carboxylic acid methyl ester was eluted first and was obtained as a colorless oil by evaporating the appropriate fractions. This compound was then taken up in 50 ml. methanol which had been previously saturated with gaseous hydrogen chloride. Evaporation yielded 1.37 g. (17%) of pure 5-ethyl-4-ethylaminothiophene-3-carboxylic acid methyl ester hydrochloride, m.p. 135.degree. C. (dec.) (methanol/ether).
EXAMPLE 31 5-ethyl-4-trifluoroacetamidothiophene-3-carboxylic acid methyl esterA solution of 4.434 g. (0.02 mol) of 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester, hydrochloride in 40 ml. anhydride pyridine was treated at 25.degree. C. with 3.14 ml. trifluoroacetic anhydride in one portion. The resulting reaction was stirred at 25.degree. C. for one hour and partitioned between 3 N hydrochloric acid/methylene chloride. The aqueous phase was further extracted (2x) with methylene chloride/methanol, (4:1). The organic extracts were combined, dried over sodium sulfate and evaporated to afford 4.85 g. (86%) of pure 5-ethyl-4-trifluoroacetamidothiophene-3-carboxylic acid methyl ester, m.p. 55.degree.-56.degree. C. (hexane).
EXAMPLE 32 5-ethyl-4-methylamino-3-thiophenecarboxylic acid methyl ester hydrochlorideA solution of 2.81 g. (0.010 mol) of 5-ethyl-4-trifluoroacetamidothiophene-3-carboxylic acid methyl ester in 30 ml. absolute tetrahydrofuran was added dropwise at 0.degree. C. to a flask containing 1.32 g. of sodium hydride (50% dispersion) in 30 ml. absolute tetrahydrofuran and 5 ml. of methyl iodide. The resulting reaction was stirred for 1.5 hours and treated sequentially with 1.3 g. sodium hydride (50%) and 5 ml. methyl iodide. After 6 hours, the resulting reaction was quenched with 25 ml. of a 20% ammonium hydroxide solution which was added dropwise. The reaction mixture was acidified with concentrated hydrochloric acid and washed (2x) with methylene chloride. The aqueous phase was made basic with concentrated ammonium hydroxide and extracted (3x) with methylene chloride/methanol (4:1). The organic extracts were combined, dried over sodium sulfate and evaporated to yield 0.734 g. of 5-ethyl-4-methylamino-3-thiophenecarboxylic acid methyl ester, as a colorless oil. This compound was dissolved in 20 ml. of methanol which had been previously saturated with gaseous hydrogen chloride and evaporated to yield 0.868 g. (37%) of crude 5-ethyl-4-methylamino-3-thiophenecarboxyic acid methyl ester hydrochloride. The product was purified by recrystallization from methanol ether to afford white needles, m.p. 172.degree.-173.degree..
EXAMPLE 33 TABLE VI
__________________________________________________________________________
EFFECT OF ORAL ADMINISTRATION OF COMPOUND A AT INCREASING CONCENTRATIONS
ON
HEPATIC FATTY ACID AND CHOLESTEROL SYNTHESIS.sup.a
Fatty Acid Synthesis Cholesterol Synthesis
.mu.moles .sup.3 H.sub.2 O/g/30 min
nmoles[.sup.14 C]alanine/g/30 min
.mu.moles .sup.3 H.sub.2 O/g/30
mmoles[.sup.14 C]alanine/g
/30 min
__________________________________________________________________________
Control
(1% gum arabic)
36.7 .+-. 2.7
685 .+-. 59 0.50 .+-. 0.06
13.9 .+-. 1.5
Compound A
18.0 .+-. 2.3***
290 .+-. 49** 0.60 .+-. 0.06
15.8 .+-. 1.6
(49%) (42%) (120%) (114%)
__________________________________________________________________________
.sup.a Charles River female rats were fasted 48 hr, then mealfed (8 to 11
a.m.) a high carbohydrate diet for 14 days. Rats weighing 180 to 210 g (1
in each group) were dosed by gastric gavage, with either 1% gum arabic or
Compound A in 1% gum arabic. The initial dose was 0.4 mmoles (89 mg) per
kg body weight and was increased by 0.2 mmoles (44 mg) per kg body weight
every other day. The experimental period consisted of 10 days, and the
doses given were 0.4, 0.6, 0.8, 1.0 and 1.2 mmoles per kg. All rats were
fed 1/2 hr after the oral dose. On the 10th day, following the 3 hr meal,
each rat received an intravenous injection (consisting of 5 .mu.Ci
[U.sup.14 C]alanine, 1 mCi .sup.3 H.sub.2 O, 12.3 mg alanine and 30.6 mg
ketoglutaric acid) and was killed 30 min later. Livers were quickly
excised, saponified, and extracted for fatty acids or cholesterol. Data
are expressed as .mu.moles .sup.3 H.sub.2 O or nmoles [.sup.14 C]alanine
converted into fatty acids or cholesterol per gram liver per 30 min.
Each value is the mean .+-. SE.
***p < 0.05
Compound A is 4amino-5-ethyl-3-thiophenecarboxylic acid methyl ester
hydrochloride.
EXAMPLE 34
TABLE VII
______________________________________
EFFECT OF ORAL ADMINISTRATION OF COMPOUND
A AT INCREASING CONCENTRATIONS ON SERUM
TRIGLYCERIDES, CHOLESTEROL
INSULIN AND GLUCOSE.sup.a
Triglycerides Cholesterol
Insulin Glucose
mg % mg % ng/ml mg %
______________________________________
Control
(1% gum 51 .+-. 3 97 .+-. 5 3.85 .+-. 0.74
165 .+-. 7
arabic)
Compound
31 .+-. 3***
79 .+-. 6*
1.91 .+-. 0.24*
160 .+-. 5
A (62%) (81%) (49%) (97%)
______________________________________
.sup.a Charles River female rats were fasted 48 hr, then mealfed (8 to 11
a.m.) a high carbohydrate diet for 14 days. Rats weighing 180 to 210 g (1
in each group) were dosed by gastric gavage, with either 1% gum arabic or
Compound A in 1% gum arabic. The initial dose was 0.4 mmoles (89 mg) per
kg body weight and was increased by 0.2 mmoles (44 mg) per kg body weight
every other day. The experimental period consisted of 10 days, and the
doses given were 0.4, 0.6, 0.8, 1.0 and 1.2 mmoles per kg. All rats were
fed 1/2 hr after the oral dose. On the 10th day, following the 3 hr meal
each rat received an intravenous injection (consisting of 5 .mu.Ci
[U.sup.14 C]alanine, 1 mCi .sup.3 H.sub.2 O, 12.3 mg alanine and 30.6 mg
ketoglutaric acid) and was killed 30 min later. Blood was collected,
allowed to clot and serum analyzed.
Each value is the mean .+-.SE
*p < 0.05
***p < 0.001
Compound A is 4amino-5-ethyl-3-thiophenecarboxylic acid methyl ester
hydrochloride.
EXAMPLE 35
The antiobesity activity of 4-amino-5-ethyl-3-thiophene carboxylic acid methyl ester hydrochloride (Compound A) was evaluated in a long-term chronic experiment in which body weight gain and food consumption were monitored at least biweekly. The study was conducted on Charles River rats receiving 10% corn oil: 60% glucose (high fat) diets. For the first 32 days of this study a dose of approximately 71 mg./kg. body weight/day was given. From day 33 until the end of the study the average daily dose was increased to 130 mg./kg. body weight/day. The study included a group of rats pair-fed to the Compound A treated rats, i.e., the pair-fed animals received the same amount of food as their Compound A paired rat consumed on the previous day. Pair feeding was terminated several days after food intake in the Compound A treated groups returned to control levels. Pair-feeding to the Compound A treated group was terminated on day 22. Upon termination of the study, carcass lipid and protein levels, serum lipids and hepatic rates of fatty acid synthesis in vivo were determined. A summary of the initial and final body weights, cumulative weight gained and food consumed and average daily food intake is presented in Table VIII. A summary of the effect of Compound A on body fat and protein is presented in Table IX.
TABLE VIII
__________________________________________________________________________
EFFECT OF COMPOUND A ADMINISTERED AS A DIETARY ADMIXTURE IN
10% CORN OIL DIET ON BODY WEIGHT AND FOOD INTAKE IN
AD LIBITUM FED CHARLES RIVER RATS IN A 63 DAY STUDY.sup.a,b
IBW FBW CBWG
CFC FI Drug Ingested.sup.c
Treatment
g g g g g/day mmoles(mg)/kg/day
__________________________________________________________________________
Control
215 .+-. 3
282 .+-. 8
68 .+-. 6
1115.1 .+-. 44.1
17.7 .+-. 0.7
--
Pair-Fed
214 .+-. 3
281 .+-. 6
66 .+-. 6
1008.0 .+-. 25.2*
16.0 .+-. 0.4*
--
Compound A
214 .+-. 3
256 .+-. 4*
41 .+-. 4*
1026.9 .+-. 25.2
16.3 .+-. 0.4
.320 (71)
.586 (130)
__________________________________________________________________________
.sup.a Female Charles River rats (10 rats per group) were fed ad libitum
the 10% corn oil:60% glucose diet. On day 1 of the experiment rats were
divided into three groups: (1) control, (2) Compound A as a dietary
admixture (71 mg/kg body weight/day, and (3) pairfed to the Compound A
treated group. Pairfeeding was terminated on day 23. On day 33 the
concentraton of Compound A was increased to 130 mg/kg/day.
.sup.b Abbreviations:
IBW = initial body weight;
FBW = final body weight;
CBWG = cumulative body weight gain;
CFC = cumulative food consumption; and
FI = food intake.
*p .ltoreq. 0.05
Compound A is 4amino-5-ethyl-3-thiophene carboxylic acid methyl ester
hydrochloride.
TABLE IX
__________________________________________________________________________
EFFECT OF COMPOUND A ADMINISTERED AS A DIETARY
ADMIXTURE IN 10% CORN OIL DIET ON TOTAL BODY
FAT AND PROTEIN IN AD LIBITUM FED CHARLES RIVER
RATS (63 DAY STUDY).sup.a
Lipid Protein
Treatment
total (g)
% of body weight
total (g)
% of body weight
__________________________________________________________________________
Control 66.8 .+-. 7.1
23.5 .+-. 2.2
54.1 .+-. 4.8
19.1 .+-. 1.6
Compound A
42.1 .+-. 4.5*
16.5 .+-. 1.7*
52.7 .+-. 0.6
20.7 .+-. 1.4
__________________________________________________________________________
.sup.a Female Charles River rats (10 rats per group) were fed ad libitum
the 10% corn oil:60% glucose diet. On day 1 of the experiment rats were
divided into three groups: (1) control, (2) Compound A as a dietary
admixture (71 mg/kg body weight/day), and (3) pairfed to the Compound A
treated group. Pairfeeding was terminated on day 22. On day 33 the
concentration of Compound A was increased to 130 mg/kg/day.
*p .ltoreq. 0.05
Compound A is 4amino-5-ethyl-3-thiophene carboxylic acid methyl ester
hydrochloride.
The following Examples 36-41 illustrate pharmaceutical compositions having 4-amino-5-ethyl-3-thiophene carboxylic acid methyl ester hydrochloride (Active Compound) as the active ingredient.
EXAMPLE 36 ______________________________________
TABLET FORMULATIONS: (Direct Compression)
Item Ingredients mg/tablet mg/tablet
mg/tablet
______________________________________
1. Active Compound
15 30 60
2. Lactose 207 192 162
3. Avicel 45 45 45
4. Direct Compression
30 30 30
Starch
5. Magnesium Stearate
3 3 3
Weight of tablet
300 mg 300 mg
300 mg
______________________________________
Procedure
(1) Mix Item 1 with equal amount of lactose. Mix well.
(2) Mix with Item 3, 4, and remaining amount of Item 2. Mix well.
(3) Add magnesium stearate and mix for 3 minutes.
(4) Compress on a suitable punch.
EXAMPLE 37 ______________________________________
CAPSULE FORMULATION
Item Ingredients mg/capsule
mg/capsule
mg/capsule
______________________________________
1 Active Compound
15 30 60
2 Lactose 239 224 194
3 Starch 30 30 30
4 Talc 15 15 15
5 Magnesium Stearate
1 1 1
Capsule fill weight
300 mg 300 mg
300 mg
______________________________________
Procedure
1. Mix items 1-3 in a suitable mixer.
2. Add talc and magnesium stearate and mix for a short period of time.
Encapsulate on an appropriate encapsulation machine.
EXAMPLE 38 ______________________________________
TABLET FORMULATIONS: (Wet Granulation)
Item Ingredients mg/tablet mg/tablet
mg/tablet
______________________________________
1. Active Compound
15 30 60
2. Lactose 188 173 188
3. Modified Starch
25 25 30
4. Pregelatinized
20 20 20
Starch
5. Distilled Water q.s.
-- -- --
6. Magnesium Stearate
2 2 2
Weight of tablet
250 mg 250 mg
250 mg
______________________________________
Procedure
1. Mix Items 1-4 in a suitable mixer.
2. Granulate with sufficient distilled water to proper consistency. Mill.
3. Dry in a suitable oven.
4. Mill and mix with magnesium stearate for 3 minutes.
5. Compress on a suitable press equipped with appropriate punches.
EXAMPLE 39 ______________________________________
CAPSULE FORMULATION
Item Ingredient mg/capsule
mg/capsule
mg/capsule
______________________________________
1. Active Compound
100 250 500
2. Lactose 99 148 --
3. Corn starch 20 30 57
4. Talc 5 10 15
5. Magnesium stearate
1 2 3
Fill weight of
225 440 575
capsule
______________________________________
Procedure
1. Mix items 1, 2, and 3 in a suitable mixer. Mill through a suitable mill.
2. Mix the mixture in Step 1 with item 4 and 5 and fill on a suitable machine.
EXAMPLE 40 ______________________________________
TABLET FORMULATIONS: (Wet Granulation)
Item Ingredient mg/tablet mg/tablet
mg/tablet
______________________________________
1. Active Compound
100 250 500
2. Lactose 147.5 100 97.5
3. Pregelatinized
25 30 60
starch
4. Modified starch
25 50 60
5. Corn starch 25 50 60
6. Magnesium stearate
2.5 5 7.5
Weight of tablet
325 500 785
______________________________________
Procedure
1. Mix items 1, 2, 3, 4 and 5 in a suitable mixer, granulate with water, and dry over night in a suitable oven. Mill through suitable mill.
2. Mix with item 6 and compress on a suitable press.
EXAMPLE 41 ______________________________________
TABLET FORMULATIONS: (Wet Granulation)
Item Ingredient mg/tablet mg/tablet
mg/tablet
______________________________________
1. Active Compound
100 250 500
2. Lactose 98.5 147.5 170
3. Polyvinyl 15 30 40
pyrrolidone
4. Modified starch
15 30 40
5. Corn starch 15 30 40
6. Magnesium stearate
1.5 2.5 5
Weight of tablet
245 mg 490 mg
795 mg
______________________________________
Procedure
(1) Mix items 1, 2, 4 and 5 in a suitable mixer, granulate with PVP and dissolve in water/alcohol. Dry the granulation. Mill the dry granulation through a suitable mill.
(2) Add magnesium stearate and compress on a suitable press.
EXAMPLE 42 4-carbomethoxy-3-keto-2-ethyltetrahydrothiopheneTo a suspension of 63.5 g. (1.176 mols) of sodium methoxide in 300 ml. of dry toluene was added dropwise at 25.degree. 229 g. (0.98 mol) of 2-ethyl-3-thia-1,6-hexanedioic-1-ethyl-6-methyl ester in 200 ml. of dry toluene. The reaction mixture warms up during the addition. After stirring overnight at room temperature, the reaction was poured into 800 ml. of water, and the toluene layer was further extracted with 200 ml. of water. The aqueous phases were combined, carefully acidified with 6 N HCl, and extracted three times with methylene chloride/methanol, 5:1. The organic extracts were dried and evaporated to afford 149.7 g. (82%) of pure 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene as a colorless oil.
EXAMPLE 43 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene oximeTo a solution of 507 g. (2.697 mols) of 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene in 327 ml. of anhydrous pyridine was added in several portions 206.1 g. (2.967 mols) of hydroxylamine hydrochloride. The reaction was allowed to proceed for 20 hours at 25.degree. and partitioned between methylene chloride/6 N HCl. The aqueous phase was backwashed two times with methylene chloride/methanol 5:1. The organic phases were dried and evaporated to afford 544.5 g. (99%) of pure 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene oxime as a pale yellow oil.
EXAMPLE 44 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochlorideA solution of 544.48 g. (2.682 mol) of 4-carbomethoxy-3-keto-2-ethyltetrahydrothiophene oxime in 0.5 l. of anhydrous ether was added (mechanical stirring) over 20 minutes to a 2.0 l. solution of gaseous hydrogen chloride in ether (saturated). The reaction was seeded with 10.0 mg. of authentic product, thus inducing crystallization. The reaction was allowed to run for 20 hours at 25.degree. and the product, which separated, was filtered off and washed well with anhydrous ether. This procedure yields 423 g. (71%) of 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochloride, m.p. 174.degree.-175.degree. (methanol/acetonitrile).
Claims
1. A process for reducing blood lipid levels in warm blooded animals which comprises administering an amount of a compound of the formula: ##STR9## wherein R is lower alkyl; R.sub.2 is hydrogen, hydroxy, lower alkoxy, or amino; R.sub.3 and R.sub.4 individually are lower alkyl, aryl, aralkyl or hydrogen; or a pharmaceutically acceptable salt thereof, in an amount effective for reducing blood lipid levels.
2. The process of claim 1 wherein said compound is: ##STR10## or a pharmaceutically acceptable salt thereof.
3. A method for reducing body fat in warm-blooded animals comprising administering a compound of the formula: ##STR11## wherein R is lower alkyl; R.sub.2 is hydrogen, hydroxy, lower alkoxy, or amino; R.sub.3 and R.sub.4, which may be the same or different, are lower alkyl, aryl, aralkyl, acyl and hydrogen; or a pharmaceutically acceptable salt thereof, in an amount which is effective as an antiobesity agent.
4. The method of claim 3 wherein the compound is ##STR12## or a pharmaceutically acceptable salt thereof.
5. The process of claim 2 wherein the compound is 4-amino-5-ethyl-3-thiophene carboxylic acid methyl ester.
6. The process of claim 2 wherein the pharmaceutically acceptable salt is 4-amino-5-ethyl-3-thiophene carboxylic acid methyl ester hydrochloride.
7. The process of claim 1 wherein the compound is 4-amino-5-ethyl-3-thiophene carboxylic acid.
8. The method of claim 4 wherein the compound is 4-amino-5-ethyl-3-thiophene carboxylic acid methyl ester.
9. The method of claim 4 wherein the pharmaceutically acceptable salt is 4-amino-5-ethyl-3-thiophene carboxylic acid methyl ester hydrochloride.
10. The method of claim 3 wherein the compound is 4-amino-5-ethyl-3-thiophene carboxylic acid.
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| 4317915 | March 2, 1982 | Confalone et al. |
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- Baker et al., Jour. Org. Chem., vol. 18, pp. 138-152 (1953) Particularly pp. 138-139 and 145 (Compounds IV and VII). Arzneim. Forsch., vol. 22, pp. 2146-2147 (1972) (English Language Summary at p. 2147, bottom of column).
Type: Grant
Filed: Mar 10, 1983
Date of Patent: Jan 31, 1984
Assignee: Hoffmann-La Roche Inc. (Nutley, NJ)
Inventors: Pasquale N. Confalone (West Caldwell, NJ), Giacomo Pizzolato (Glen Ridge, NJ), Milan R. Uskokovic (Upper Montclair, NJ), Marianne Rouge (Basel)
Primary Examiner: Alan Siegel
Attorneys: Jon S. Saxe, Bernard S. Leon, George W. Johnston
Application Number: 6/474,072
International Classification: A61K 3138;
